brake bleeding firm now spongie.

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dennday67

dennday67

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Okay for starters I've done quite a few brake jobs and a few disc brake swaps but never had this problem.

I installed a 1985 5th Ave rebuilt mc (bench bled) with the ar engineering adapter plate using the stock push rod. The disc brakes are 73+ with the proportioning valve from the same car. Front calipers are rebuilt units with new brake lines and hoses. Both with copper gaskets one on each side of the line at the caliper. The rear are 10" drums with new wheel cylinders.

I bled the wheels starting from the back right like I always do and work my way around farthest from the mc to the closest. Everything was going good and had no leaks that I can see but when I bleed the front right the peddle goes to ****. And takes 4-6 pumps to build back up. But I see no air (I use a home made setup with a mayson jar hard brake line and clean rubber hose to the bleeder). Go to the next and still no air. So I got to thinking about how some say the fronts are a pain to bleed and my bleeders are facing forward and the car was level on Jack stands so I jacked the front up another 2-3 inches and try again. And got some air out of the front right. And none from the front left. So I go to bleed the whole system from the beginning again and my buddy says the peddle feels like **** in the time it takes me to go from one side to the other. Any ideas as to what's going on? I'm letting it sit and doing other things hoping the air in the system will settle and can push it out.
 
Just a guess, a defective master cylinder? You should build pressure as you remove air from the system. Have you any leaks around the proportioning valve?
 
I double checked all connections and don't see any leaks. I have to wait till my buddy gets back to try again.
 
Are you bleeding with the engine running? Had the same problem with
A Plymouth breeze bleed it almost two days before I found out there is
Valve that is electrically controlled by for antilock brakes. Bleed it with the engine running and viola!
 
Open all four bleed screws on the wheel cylinders remove the MC cap and see that you get fluid
coming out just from gravity just to make sure you don't have any restrictions
 
I've never gravity bled brakes because that always sounded sketchy to me... how long do you leave them open?
 
Just long enough to get good flow from them,it should flow out of all
four of them remember to keep check on the level in the MC.
After that then pressure bleed them as normal. It sounds like you
Still have some air trapped in the system somewhere
 
Oh yea when you bench bleed the MC did you tap on it to help get air out?
And tap the wheel cylinders at any low places in the lines
 
I invested $20 in speed bleeders and their amazing! Bled my whole system by myself twice in five minutes! I know this doesnt help with the problem but it might help so you dont gotta wait for your buddies help lol
 
I bought a might vac bleeder once and it was junk. Never worked then I made my jar and did mine solo with it.
 
dennday67 said:
I bought a might vac bleeder once and it was junk. Never worked then I made my jar and did mine solo with it.
Click to expand...

I use a jar and tygon tubing and do them by myself this way also
All you do is fill the jar with about a 1/4 of clean fluid stick the hose down in
the fluid other end on the bleeder open it the pump away on them as long
As the end of the hose is in the fluid it can't suck air back in work great
 
That exactly how I've done it in the past. be sure to coat the threads of the bleeder screws with wheel bearing grease.
 
Okay I gravity bled the brakes till the mc was half way down with fluid flowing from all 4 corners. Closed them off in order farthest from the mc first. Checked peddle and firm then went to pressure bleed it and it goes to **** on the front right still. Tried it nose up down and level
 
I gravity bled it again with the mc level till it ran almost a whole Res full but not completely out. Top the Res off capped it and closed the bleeders again in the same order. Checked the peddle and the first pump took half a pump before firm pressure. And before I did it this time I had my buddy hold the peddle down and cracked the mc lines to see if there was air in it and the front system might of had a bit. Were going to give it a day or so and see how the peddle feels. I'm still stumped why the front passenger turns the peddle to **** but no air comes out. We also noticed it seems worse if the peddle goes all the way to the floor while bleeding the front.
 
A coworker is going to lend me his vacuum bleeder and I guess ill give it a try this weekend.
 
dennday67 said:
it seems worse if the peddle goes all the way to the floor while bleeding the front.
Click to expand...

The master may be losing prime. Be sure the pedal/ piston is coming all the way back and uncovering the ports in the master, which lets the cylinder refill.

Also there may be something WRONG with the master and it may be allowing air INTO the master through the rear piston seal. This would be happening on the upstroke.
 
Two questions. You said rebuilt calipers, when you put them on did you put them on with the bleeder in the UP position? Have you adjusted the rear brakes up?
 
The front calipers are mounted with the bleeders towards the front and lines to the rear, the rear shoes are adjust out to contact the drum with a little drag. I'm not sure if my buddy was letting the peddle come all the way up to let it fully refill. I hope the mc isn't messed up if so that was a waist of a $6 keeper bushing. Is there an over travel on mc that could be letting air in? I read that the system should be bled with the caps off and I've been putting the caps back on when pressure bleeding to avoid getting dot3 on my new paint. Could that be the problem as it has a lot of vacuum when I pull the caps off? I've never delt with the plastic Res mc.
 
The above statement makes me wonder.

Tighten the 'ELL out of the rear shoes, get 'em TIGHT so the wheels won't turn until you get them bled.

When you bleed (and maybe you are) have your buddy pump up pedal with ALL BLEEDERS closed. Open one bleeder only, and close it when fluid starts to slow down (pedal to floor) CLOSE the bleeder BEFORE you allow your partner to release the pedal back up.

Then pump the pedal AGAIN if necessary to get a pedal.

There should be a retainer that prevents the master piston from returning too far. To repeat, I'm wondering if it's returning far enough.

You should be able to pump up a pedal, hold it, and remove the filler cap on the master, and release the pedal. You should see movement of fluid back out the ports in the master floor. Older all drum ones typically actually "fountain" up above the fluid.
 
Yep, bleeder on top?. Dash brake light working? You can send the prop valvle off, bleeding. Feel a click when depressing? It's off center. Have buudy step on pedal, loosen a rear until click, or brake light goes off. Never ever push the pedal to the floor, while bleeding.
 
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